
function f(p) {
  console.log(Array.from(arguments)); //[ 'xue', 'shi', 'yang' ]
    p = 2;
    console.log(Array.from(arguments)); //[ 2, 'shi', 'yang' ]
}
f('xue', 'shi', 'yang')
function f1() {
  return 3
}
function def(obj, key, val){
  Object.defineProperty(obj, key, {
    value: val,
    enumerable: true,
    configurable: true,
    writable: true,
  })
}
const obj = {name: 'xx', age: 12};
def(obj, 'age',f1)
console.log(obj.age)